This grant application requests support for the development of a methodology for the design of composite medical information systems capable of dynamic system evolution in response to user needs. The design methodology will be tested by the implementation of a composite medical information system in an operational environment that combines clinical and research activities in a manner that we believe to be important for the future of computers in the delivery of health services. Specific aims are to perfect the design methodology, to implement a generalized query evaluator, to implement a local and a regional interconnection network, to extend methods for database consistency assurance, to install the experimental medical information system in a combined clinical and research setting, to develop analysis tools for system performance prediction and to evaluate the ease with which the experimental system can accommodate dynamic restructuring.